1. Field of the Invention
The present invention relates to a recording tape cartridge which accommodates, in a case, a single reel onto which recording tape such as a magnetic tape or the like is wound, principally for use as a recording/replaying medium for computers and the like.
2. Description of the Related Art
Conventionally, a magnetic tape cartridge has been known in which a magnetic tape, which is used as a data recording/replaying medium for computers or the like, is wound onto a single reel and this reel is accommodated in a case. At a distal end of such a magnetic tape, a leader member, such as a leader pin, a leader tape, a leader block or the like is provided. Drawing-out means, which is provided at a drive device side, draws the leader member out through an opening aperture of the magnetic tape cartridge and winds the magnetic tape, which is fixed to the leader member, onto a drive device side winding reel.
A reel gear is provided in an annular form at a lower face center of the reel and exposed through an opening hole, which is formed in a lower face of the magnetic tape cartridge. A drive gear, which is provided at a drive device side rotation shaft, meshes with the reel gear. By this structure, the reel is driven to rotate. When the reel of the magnetic tape cartridge and the winding reel of the drive device are rotated at the same time, data can be recorded to the magnetic tape and/or data that has been recorded to the magnetic tape can be replayed.
Such magnetic tape cartridges take up little space when stored and can record large amounts of information. As shown in FIGS. 7 to 9, a position of the opening aperture and a type of door that opens and closes the opening aperture are different for the different types of leader member. Specifically, in the case of a leader pin 60, as shown in FIG. 7, an opening 68 is formed in a side wall 64 of a case 62, which wall is parallel with a direction of loading into a drive device (the direction of arrow P). This opening 68 is opened and closed by a door 66, which slidingly moves in a direction the same as the loading direction.
However, because the opening 68 is provided at the side wall 64 of the case 62 in this manner, it is necessary that the drive device side drawing-out means turns and guides in the leader pin 60 from a sideward direction left or right of the case 62 when drawing out the leader pin 60. Therefore, a space for this turning and guiding in by the drawing-out means must be conserved at the drive device side. Moreover, a structure for the turning and guiding in by the drawing-out means is complicated, and leads to a disadvantageous increase in size of the drive device. In addition, there is a problem that a drawing-out path of the magnetic tape T becomes long.
In the case of a leader tape 70, as shown in FIG. 8, an opening 78 is formed in a front wall 74 of a case 72, which wall intersects the direction of loading into a drive device (the direction of arrow P). A door 76, which opens and closes this opening 78, is a swivel-type door which rotates forward about a support shaft 75 which is supported at a corner vicinity of the case 72. However, when the opening 78 is formed in the front wall 74 of the case 72 in this manner, although there is no requirement for the drive device side drawing-out means to turn and guide in the tape, the door 76 opens outward by a large amount. Therefore, it is necessary to reserve space at the drive device side such that the door 76 will not be impeded when opening the opening 78. As a result, the drive device disadvantageously becomes larger.
In the case of a leader block 80, as shown in FIG. 9, an opening 88 is formed by cutting away a corner portion 84 at a front side in the drive device loading direction. The opening 88 is opened and closed directly by the leader block 80. When the leader block 80 opens and closes the opening 88 in this manner, there is a problem in that the leader block 80 is susceptible to the occurrence of damage and soiling. Specifically, because the leader block 80 engages at a drive device side reel hub 86 and structures a portion of the reel hub 86, even a small amount of damage or soiling that would not be a problem if the leader block 80 was employed as a usual door can cause difficulty for engaging with the reel hub 86, and this can have a disadvantageous effect on running of the magnetic tape T.
Moreover, the leader block 80 is anchored only at peripheral portions of the opening 88. Consequently, there is a problem that the leader block 80 detaches easily when the magnetic tape cartridge is dropped. Furthermore, because the leader block 80 is larger in size than the leader pin 60, there is a problem in that there are many more constraints on the form of the case. Therefore, the leader pin 60, which functions separately from a door, can be said to be preferable to the leader block 80, which is combined with a door.